Thionyl Chloride and Phosphorus Trichloride

Compare geometries, atomic charges and electrostatic potential maps of thionyl chloride and phosphorus trichloride. How are they similar How are they different Can you redraw the Lewis structure of SOCI2 so that it gives abetter description of the electrostatic potential map  

Alcohol attack generates an unstable intermediate that undergoes nucleophilic attack by CL at carbon. Compare electrostatic potential maps of methanol, thionyl chloride intermediate, and phosphorus trichloride intermediate. What features of these maps are consistent with an electrophilic reactive intermediate  

Electrostatic potential map for phosphorus trichloride shows negatively-charged regions (in red) and positively-charged regions (hi blue). 

LUMO of thionyl chloride reveals the best electron-acceptor sites. 

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Using a glass U-tube as a reaction tool, Nakamura and coworkers expanded phase-vanishing methods to include reagents Hghter than fluorous solvents, such as thionyl chloride and phosphorus trichloride [19]. 

Oleoyl chloride has been prepared by treatment of oleic acid with thionyl chloride,3 phosphorus trichloride or pentachloride, and oxalyl chloride.4 The highest yield (86%) reported was secured by use of oxalyl chloride in carbon tetrachloride, but the more economical phosphorus trichloride gave a yield of 60%. The standard procedures for obtaining aliphatic acid chlorides have been described many times without inclusion of details other than physical properties. Only references to the procedures useful in the laboratory are given. 

Because they are readily available from a number of synthetic reactions, carboxylic acids are the most common starting materials for the preparation of the other members of this family. Conversion of a carboxylic acid to an acyl chloride provides access to any of the other derivatives because the acyl chloride is at the top of the reactivity scale. Bui how can the acyl chloride be prepared from the acid when the acid is lower on the reactivity scale This can be accomplished by using an even more reactive compound to drive the equilibrium in the desired direction. The reagent that is employed in the vast majority of cases is thionyl chloride, SOCl2. Phosphorus trichloride, PC13, and phosphorus pentachloride, PC15, are also used occasionally. Examples are provided in the following equations ... 

Cl 64.24%. SeCI4. Prepd by the action of an excess of chlorine on selenium Berzelius, cited in Meltor s vol X, 898 (1930) by the action of thionyl chloride or phosphorus trichloride on selenium oxychloride and by the action of phosphorus pentachloride on selenium oxide Michael is. Z Chem. [2) 6, 460 (1870) by the action of anhydr selenic acid on acetyl chloride at 0 Lamb, Am, Chem. J. 30,209 (1903). Crystal structure Shoemaker, Abrahams, Acta Cryst. 18,... 

When a sulfonic acid such as butanesulfonic acid (111 see Chapter 16, Section 16.9) is treated with thionyl chloride or phosphorus trichloride, the product is a sulfonyl chloride. In this case. 111 is converted to what is known as butanesulfonyl chloride, 112. When 112 reacts with an alcohol, a sulfonate ester is produced. Treatment of 112 with ethanol leads to 113 (ethyl butanesul-fonate) and treatment with methanol leads to 114 (methyl butanesulfonate). A variety of sulfonate esters can be prepared in this manner. It is also possible to react a sulfonic acid with an alcohol under acid catalysis conditions to give sulfonate esters, but that reaction is not discussed until Chapter 20. 

Phosphorus trichloride reacts with thionyl chloride to form phosphoryl chloride, thiophosphoryl chloride and phosphorus pentachloride ... 

The same product is obtained when thionyl chloride and pyridine are used in place of phosphorus trichloride [74d]. 

Thionyl chloride, SOCl2, and phosphorus trichloride also gave HP03. 

The conversion of a carboxylic acid to its halide is usually accomplished by thionyl chloride or phosphorus halides. Phosphorus trichloride and glacial acetic acid give acetyl chloride (67%). The other product is phosphorus acid. Phosphorus pentachloride is converted to phosphorus oxychloride (b.p. 103°), from which the acyl halide is sometimes separated with difficulty. This reagent, however, finds use in the preparation of certain higher-molecular-weight halides. .. Most acyl bromides are made from phosphorus tribromide. ... 

Chloromorphide results from the restricted action of hydrochloric acid on morphine or a-chloromorphide [71] and also in 5 per cent, yield during the preparation of the a-isomer by the action of thionyl chloride on morphine [19]. It is probably the product of interaction of a-iso-morphine and phosphorus trichloride [14, 16]. It can be methylated to /3-chlorocodide by diazomethane [69]. 

Acetyl chloride was formerly manufactured by the action of thionyl chloride [7719-09-7], Cl2OS, on gray acetate of lime, but this route has been largely supplanted by the reaction of sodium acetate or acetic acid and phosphorus trichloride [7719-12-2] (24). A similar route apparently is still being used in the Soviet Union (25). Both pathways are inherently costly. 

Other halides which have been added to carbodiimides include phosphorus trichloride, phosphorus oxychloride, sulfur dichloride, sulfuryl chloride, and thionyl chloride ( ), and product formation was judged on the basis of disappearance of the cumulative double bond absorption of the carbodiimides. 

Amino-pyridazines and -pyridazinones react with monomethyl- or iV,A-dimethyl-formamide and other aliphatic amides in the presence of phosphorus trichloride, thionyl chloride, phosgene or benzenesuUonyl chloride to give mono- or di-alkylaminomethyl-eneamino derivatives. The same compounds can be prepared conveniently with A,iV-dimethylformamide dimethyl acetal in high yield (Scheme 50). 

Jsomerides of Morphine and Codeine. When morphine is treated with thionyl chloride, phosphorus trichloride or tribromide, the alcoholic hydroxyl group is replaced by the halogen, forming a-chloromorphide and bromomorphide respectively. The former on treatment with concentrated hydrochloric acid is converted into /3-chloromorphide. Schopf and Hirsch have provided evidence that the two are structural isomerides. With the same reagents codeine yields a parallel set of compounds, viz., a- and -chlorocodides, and bromocodide. The chief characteristics of these products may be summarised thus —... 

When there is no diluent, organic acid chlorides and metal halides react very violently with DMSO. This goes for acetyl chloride, benzenesulphonyl (C6H5SO2CI), cyanuryl chloride, phosphorus and phosphoryl trichlorides, tetrachlorosilane, sulphur, thionyl, and sulphuryl chlorides. With oxalyl chloride, the reaction is explosive at ambient temperature, but can be controlled at -60°C in a solution with dichloromethane. The dangerous reactions are thought to be... 

Another general method for converting alcohols to halides involves reactions with halides of certain nonmetallic elements. Thionyl chloride, phosphorus trichloride, and phosphorus tribromide are the most common examples of this group of reagents. These reagents are suitable for alcohols that are neither acid sensitive nor prone to structural rearrangement. The reaction of alcohols with thionyl chloride initially results in the formation of a chlorosulfite ester. There are two mechanisms by which the chlorosulfite can be converted to a chloride. In aprotic nucleophilic solvents, such as dioxane, solvent participation can lead to overall retention of configuration.7... 

Substituted phenyl salicylates can be prepared by heating salicylic acid and the appropriate phenol in the presence of phosphorus oxychloride,34 5 phosphorus trichloride,4 5 phosphorus pentachloride,4 6 phosgene,4 or thionyl chloride,4 or by heating the phenol and salol.7... 

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